Joe Hockey has called for “a mature debate” on raising the retirement age to 70 and for a discussion about aged-pension asset rules while defending the paid parental leave scheme promised by the prime minister, Tony Abbott.

The Treasurer, who is 48, speculated that his generation might have to work until 70 to achieve a particular quality of life and to maintain a sustainable welfare system.

Labor’s finance spokesman, Tony Burke, seized on Hockey's comments as a broken promise given that, before the election, Abbott had ruled out any changes to the aged pension.

“[Abbott] made a number of promises: no cuts to health; no cuts to education; no changes to pensions; no cuts to the ABC and SBS,” Burke said. “That ‘no changes to pension’ promise is about to be broken, and that was made clear today by Joe Hockey.”

The Treasurer renewed his pledge to release the Commission of Audit report before the budget on May 13, and said the Coalition’s first budget would be a reflection of the report.

Hockey warned that all Australians would have to contribute to repairing the budget, “including politicians”.

The former Labor government announced an increase in the retirement age from 65 to 67 in 2023-34. Hockey said other countries, including Britain, were also raising the retirement age as people’s life expectancy rose.

Asked if the government should be debating a retirement age of 70, Hockey replied: “That’s certainly one of the issues that needs to be addressed.”

Burke said Labor had gradually increased the pension age from 65 to 67 and that the government needed to consider those whose work involved physical labour.

“For a whole lot of people in jobs that involve physical labour, a shift in the retirement age can be a very big deal, and simply quoting statistics about how long people are living doesn’t actually get you there for the impact that this has on real people’s lives,” Burke said.

The Treasurer, when asked about the fact that 80% of people who were more than 65 years old and collected an aged pension also held $1m in assets, said that needed to be discussed, thus raising the prospect of examining asset tests for the aged pension.

The pension is linked to a percentage of average male earnings, and pension groups have expressed disquiet that the government could link the pension to the consumer price index, which has been a lesser rate than earnings.

Hockey noted that in the US, 60% of male workers had had a “real cut” in income, as opposed to in Australia, where real income had risen. Australian male earnings may not always be a “higher rate” than CPI, he said, “so we have to look at how sustainable pension increases are”.

Hockey said Australia needed a health and welfare system that appropriately dealt with changing demographics. “It may be the case that my generation has to work for an extra three years,” the Treasurer said.

“The fact is [that] … one in every three children born today will live to 100 so, quite frankly, we need to redesign our systems to manage and celebrate the fact that we are all living longer and maintain[ing] a good quality of life along the way.”

Hockey welcomed signals by seniors groups, including National Seniors, that “a mature debate” was required. “This is not a battle between the generations,” he said. “This is about the quality life that we not only want to live ourselves, but we want to leave to our children.”

Hockey defended Abbott’s signature policy, the paid parental leave scheme, that pays women on salaries of up to $150,000 for six months while they are on maternity leave.

“The paid parental leave scheme is about getting women back to work to pay for the pensions of tomorrow. That’s what it’s about.

“It’s about people going back to work, earning money, paying tax and being able to afford the pension system and the aged-care system and the health system that senior Australians and others want to have.”

Hockey acknowledged Australia had had 22 years of continuous economic growth, which he said was “one of the longest periods of economic growth in global history” but he warned that Australians could not bank on growth for the next 22 years.

If the government did not fix the budget, Australia would end up $667bn in debt, he said.